1. Field of the Invention
This invention relates to and is directed to an apparatus for the collection of fuel spillings from fuel supply devices and, more particularly, an apparatus which collects said spillings underground after they have passed through a filtering system which prevents any large solid materials from collecting in the reservoir area of the apparatus, and also allows for the addition of certain fill material between the surface and the filter system to enhance the fire safety features of this device.
Gasoline spill collectors in various embodiments have previously been available to the general public. The general idea behind prior art devices as well as related underground leak protection apparatus has been to in some way collect the material, normally fuel, which has leaked or spilled in one place. Some of these devices also allow for the material collected to be directed into the vapor recovery system. Vapor recovery systems normally found in use today include those systems disclosed in U.S. Pat. Nos. 3,756,291 and 3,815,327. Other systems have also been developed to detect and prevent leaks from underground storage tanks and their associated lines to prevent possible ground water contamination such as the one disclosed in U.S. Pat. No. 4,161,957.
Generally it is considered desirable to place fuel spill collection apparatus immediately below the fuel dispensing islands normally found in gasoline stations and truck stops. Relatively recently a significant amount of concern has been directed to ground water contamination which can occur due to spills or leaks of fuel supplies from fuel supply sources into the ground and continuing to underground water systems which are eventually tapped as sources for water utilized in human consumption. Spillage can occur when gasoline tanks are filled to overflow levels, as well as when maintenance or service is conducted on the fuel supply pumps. Under such circumstances a significant amount of gasoline over a period of time can leak into the ground below the islands.
The prior art generally has disclosed devices which merely hold and accumulate fuel spillings underground until removed by some means or by virtue of connection to a vapor recovery system, holding tank or the like. This can cause a significant fire hazard. Excess fuel leaked onto the ground is fire hazard enough however, when a significant amount of fuel has been accumulated in a central location an even greater hazard has been developed. Further, without some type of filtration system between the source of fuel and collection point it is possible for solid particles such as rock, sand or even flammable solids to fall into the containment system, thereby contaminating the fuel or obstructing the operation of mechanisms located within the device.
The prior art devices also allow the possibility of flammable objects, or even worse, items which have already begun to burn to fall into the fuel containment reservoir of the fluid collection apparatus. This can cause what is known as a "hot fire" within the containment box itself.
2. Prior Art
Therefore, there exists a need for an improved under-dispenser containment device which not only prevents the accumulation of solid objects in the containment reservoir, but also prevents a hot fire within the containment box.
U.S Pat. No. 4,960,346 issued to Tamayo discloses a double-walled cylindrical bucket style unit having a floor which accepts and corresponds to the fill pipe. The inner-wall of the unit is of the bellows type to prevent vertical expansion and retraction for changing temperatures and the floor of the unit is equipped with a removable inspection plug which permits access to the soil underneath for sampling and the like.
U.S. Pat. No. 4,793,387 issued to L. J. LaBlanc, et al. discloses a overfill spillage protection device utilized to capture fuel spilled from tanks at the fill pipe. This unit surrounds the fill pipe as well as providing a cover therefore. The unit contains a single-walled portion immediately below the cover and a double-walled portion with an internal bellows type wall and an external straight wall. The internal bellows wall allows for expansion and contraction of the unit due to changes in temperature and the like.
U.S. Pat. No. 4,807,675 issued to Sharp discloses an overfill assembly with a removable lid. This patent discloses a device to be used with storage tanks, more specifically underground gasoline storage tanks. The assembly comprises a dump tank with a fill pipe mounted therein. The fill pipe extends through the dump tank's bottom and is in communication with the storage tank. A removable central point compression sealing lid member allows for ready access to the fill pipe. A valve mechanism in the dump tank allows for controlled emptying of any spilled liquid accumulated in the dump tank to the storage tank.
U.S. Pat. No. 4,842,163 issued to Bravo discloses a gasoline collector pit box and submersible unit box. This invention is directed to an apparatus which incorporates an open collecting pit to be placed underneath gasoline fuel dispensers, a means for providing a signal when a predetermined amount of gasoline has accumulated in the collection pit, means to selectively drain accumulated gasoline, and a means to amplify the effect of the gasoline accumulated. This invention does not incorporate a means for filtering the collected gasoline fuel for accumulation in the collection pit. Instead, Bravo discloses a completely open containment pit which is susceptible to "hot fires" and can allow for the contamination of fuel accumulated therein. Bravo further discloses the use of a drain at the bottom of the collection pan which can be hooked into the vapor recovery system. Bravo discloses the use of a ball valve to allow for the opening and closing of the drain as well as a filter on the drain to prevent any contaminants from filtering into the drainage system. Bravo still further discloses a preferred embodiment which can be utilized in connection with a submersible pump. Disclosed as part of this embodiment is an aperture in the bottom of the containment pan to allow for the extension of a horizontal tube through the floor of the collector to accommodate the conduit of the pump that extends down to the underground storage tank. Neither of these embodiments discloses the use of any type of filter means or more specifically any type of filler material through which any spillings must pass before accumulation in the containment reservoir. Without such filtering means, the propensity for hot fires and other types of contamination of the accumulated spillings are enhanced.
U.S. Pat. No. 4,926,899 issued to T. Argandona discloses a transition conduit system for fuel pumps which incorporates a conduit piping arranged between a fuel storage tank and an aboveground fuel pumping unit. This device is essentially a hollow conduit which avoids earth contamination problems due to its leak-proof nature.